P43DE3 + ADATA ax3u1600gb2g9, BIOS settings

[nobugsonme]

I thought my computer was rocking DDR3 @ 1600 until I upgraded to a EVGA GeForce GTX 570. According to EVGA the card is much more sensitive to memory settings than my older card. Well, I guess I hard-set the timings, but the mobo had other settings which limited the RAM. The graphics card "worked" and always passed tests, but the framerate is terrible and I'd receive an occasional BSOD due to memory management. However, several memtests never returned any errors for the RAM (both together and individually). I found that the board/BIOS was limiting the RAM to 1333. I've can't seem to tweak the settings in BIOS to get it to run at 1600 without hitting something that prevents the computer from booting. I've attempted to get help from both the RAM and mobo manufacturer, but they're pointing fingers at each other (though ASRock support suggested upgraded the BIOS to take care of some known dual-channel issues, which did seem help, a little). I know what the RAM settings are supposed to be, but some of the terminology in the ASROCK BIOS is unfamiliar to me. I hope the ASROCK die-hards here can help.

• Operating system: MS Windows Professional 7 64-bit
• Motherboard: ASRock P43DE3, BIOS version 1.50 (9/20/2010)
  ASRock > Products > P43DE3
• CPU: Intel Core 2 Duo E8500 @ 3.16GHz
• RAM: A-Data Dual-Channel DDR3-1600G 2GB
  XPG? Gaming Series DDR3, Specifications, Overclocking, Gaming, Memory Modules, OC, Gaming Series, Gaming Series, XPG, Welcome to ADATA
  Two of ax3u1600gb2g9-ag
  Two of ax3u1600gb2g9-2g
  both are specified CL 9-9-9-24 and 1.65V (though the ax3u1600gb2g9-2g specifies 1.65-1.85V)
• GFX: EVGA SuperClocked 012-P3-1573-AR GeForce GTX 570
  EVGA | Products

So my question is, how can I perfectly set my motherboard to meet all the necessary specs? I'm not looking to OC, at this point, I'd be happy to just get what I paid for, ya know?

Bonus question... the RAM specifies 1.65V, but the mobo only offers something like 1.645 and 1.659. Shoot high, or low?

Thanks for your help!

[nobugsonme]

Okay, I've received the following reply from ASRock support:

Please check under BIOS setup and verify your processor bus is 266MHz (x) P4=1333MHz with Ratio(multiplier)9.5
Check under SDRAM Frequency and voltage is set for 1.65 volts as you described your ram and bus 800MHz(x) 2 Dual Data Rate =1600MHz

The BIOS multiplier is already at 9.5, and the only thing related to CPU bus I can find is the FSB to CPU bus, which, when I set to 266MHz, still doesn't allow me to select the DRAM data rate at 1600.

ADATA replied with the following:

Frequency: 1600mhz

Latency: 9-9-9-24

Voltage: 1.55v to 1.65v (every board is different)

So, the answer to the bonus question seems to be "shoot low".

Is it time to go with a newer mobo with better DDR3 1600 support?